I recently started having issues with my Volvo Automatic Climate Control ECC unit. The dreaded flashing lights. So I pulled codes, and found lots of issues, the temp fan, the blower motor, damper motor and others. I thought that the Automatic Climate Control ECC unit had given up the ghost. After looking into it, I found the temp sensor was working correctly, and the blower motor was woking properly also. Upon looking into the damper motor, I found that it was not working.
So, like any good do it yourselfer, I took the damper motor apart. I figured if it’s broken, I can’t break it anymore. Upon opening the housing, I found the circuit board covered in white grease.
The black half circles were covered in grease also. I cleaned it off, and plugged it back in. all the codes went away, and the motor operated normally. These contacts touch the black half circles:
The grease is from the gears in the reduction system, and must have gotten on the contacts over the years. Put everything back together, and all is well. So, If you get the dreaded flashing lights, this is one more place to check before replacing parts.
Note: It’s possible to eject the ECC unit for the back but you would pull the radio out first. The ECC unit has very sharp edges, so use some protection when ejecting the unit and handling. To access the inside you have four screws to remove. Two screws on each side. Some have used use a 9 volt battery on the two solder lugs at the far edge of the circuit board to turn on the motor for testing.